Drosophila Culturing for Gnotobiotic Studies

Drosophila were cultured at 25°C on a standard yeast/cornmeal medium containing 10 g.L⁻¹ agar (VWR, ref. #20768.361), 80 g.L⁻¹ cornmeal flour (Westhove, Farigel maize H1), 50 g.L⁻¹ inactivated dry yeast (Bio Springer, Springaline BA95/0-PW), 5.2 g.L⁻¹ Methylparaben sodium salt (MERCK, ref. #106756) and 4 ml.L⁻¹ of 99% propionic acid (CARLO ERBA, cref. #409553). Germ-free animals were obtained from bleached embryos cultured on autoclaved conventional medium. When needed GF stocks were maintained during few generations on antibiotic supplemented food (final concentration: 50 µg.L⁻¹ ampicilline, 50 µg.L⁻¹ kanamicine, 15 µg.L⁻¹ erythromycin, 50 µg.L⁻¹ tetracycline) to avoid bacterial contamination. Drosophila y,w flies were used as the reference strain in this work. The following mutant lines were used: y,w,Dredd^F64 and y,w;;Relish^E20[34] (link).